This invention relates to automatic chemical testing apparatus, and more particularly to test selection and indicator means therein.
The context for the present invention is the type of chemical analyzer in which a number of samples are provided, each to have a selected number of different chemical tests performed thereon. The number of tests performed on one chemical sample may differ from the number of tests performed on another chemical sample. Preferably the samples are placed in means for holding a plurality of samples. A different test is performed on each of a number of aliquots of one sample. Test selection means are operated to produce instructions to the apparatus. Selected aliquots are each reacted with particular reagents injected therein in response to the instructions. At a subsequent time, reacted aliquot and reagent mixtures are measured for a change to indicate the results of each of the tests, as, for example, by spectrophotometric analysis. An example of a highly effective apparatus is disclosed in commonly assigned U.S. Pat. No. 3,728,080 to John J. Moran issued on Apr. 17, 1973, the disclosure of which is incorporated herein by reference. A further form of such apparatus is disclosed in commonly assigned U.S. Pat. No. 4,043,756 to David E. Sommervold issued Aug. 23, 1977, the disclosure of which is also incorporated herein by reference. The apparatus disclosed in both these patents successfully performs all of above-recited functions. In accordance with the present invention, it is desired to provide further convenience and efficiency in an operator's operation and use of the test selection means, including displaying to the operator which tests have been selected for each sample in a manner to further facilitate use of the test selection means.